The verdict on what punishment she will face, expected within the day, could upend politics in France.
Le Pen, head of the far-right National Rally (RN), is the front-runner in opinion polls ahead of France's 2027 election.
Prosecutors have asked that Le Pen face an immediate five-year ban from public office if found guilty, regardless of any appeal process, using a so-called "provisional execution" measure.
Judges can adopt, modify or ignore the prosecutors' request.
An automatic five-year ban would hammer Le Pen, 56, a three-time presidential contender who has said 2027 will be her final run for top office. She would retain her parliamentary seat until the end of her mandate.
Le Pen, who did not speak to reporters as she arrived in court, has accused prosecutors of seeking her "political death", alleging a plot to keep the RN from power that echoes claims made by US President Donald Trump about his legal woes.
Le Pen, the RN and two dozen party figures were accused of diverting European Parliament funds to pay France-based party staff.
The defendants said the money was used legitimately and the allegations define too narrowly what a parliamentary assistant does.
However judge Benedicte de Perthuis ruled: "It was established that all these people were actually working for the party, that their (EU) lawmaker had not given them any tasks."
"The investigations also showed that these were not administrative errors ... but embezzlement within the framework of a system put in place to reduce the party's costs."
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